The all-powerful French Minister of Police is looking for participants in the impending assassination attempt on the Emperor; blackmail, bribery, intelligence connections and a love letter from Napoleon are involved, from which it follows that the possible killer of the Emperor is his illegitimate son. The action of the novel takes place in the social salons and brothels of Paris, on a plantation and in a witch's hut in New Orleans and, finally, on the island of St. Helena, where events inexorably roll towards a fatal outcome.